The above recipe was found in a cookbook.
1 and 1/2 cups all-purpose flour
1/4 teaspoon salt
3/4 cup butter or margarine
1/2 cup firmly packed brown sugar
1 egg, separated
1/2 teaspoon vanilla extract
1 and 1/2 cups finely chopped pecans
Oven : 375 degrees
Sift flour with salt. Cream butter in mixing bowl. Gradually add brown sugar. Continue creaming until light and fluffy. Blend in egg yolk and vanilla extract. Add sifted dry ingredients; mix thoroughly. If desired, chill 1 hour, for easier handling. Shape dough into balls 3/4 inch in diameter. Dip into slightly beaten egg white, then into pecans. Place on ungreased cookie sheets. Press deep hole in center of each cookie with floured thimble or finger. Bake at 375 degrees for 12 to 15 minutes until light golden brown. Fill hollows with jam, jelly or tinted cream butter frosting.
My own note : These cookies seem as if they would be easy to make.